Method and apparatus for starting flow of wells



Feb. 18, 1958 `c. c. CARLISLE 2,823,620

METHOD AND APPARATUS Fon STARTING FLOW oF WELLS Filed Sept. 6, 1952 2Sheets-Sheet l n I. Il

l. l' /I b- Trae/vifs Feb. 18, 1958 c. c. CARLISLE METHOD AND IPPARATUSFOR STARTING FLOW OF WELLS Filed Sept. 6, 1952 2 Sheets-Sheerl 2ATTOP/VYS United States Patent METHOD AND APPARATUS FOR STARTING FLOW 0FWELLS Charles C. Carlisle, Tulsa, Okla.

Application September 6, 1952, Serial No. 308,236

6 Claims. (Cl. 10S- 232) This invention relates to an apparatus forflowing wells by the gas lift method and more particularly to a methodof'starting oil ow in vsuch vwells after the gas pressure has failed orthe wells have been shut down. For example, an oil well often flows whenit is first drilled in under the formation pressure but after a shorttime the gas which produces the flow drops in both pressure and volumebelow that required to maintain the oil flow. When that state isreached, a gas may be injected into the oil near the bottom of the wellunder artificial pressure and the ow may be maintained. However, whenonce the flow is started, the gas must be supplied in a continuousstream, for if the supply is even momentarily interrupted the oil flowwill cease and the well must be restarted.

In starting flow of a well it is difi'icult toovercorne the excessivehydrostatic head of oil which ordinarily accumulates in such wellsduring interruption of the gas supply or shut down periods, because suchexcessive hydrostatic head cannot be removed by direct application of areasonable gas pressure. For example, in the more common type of gaslift, the gas is passed into a well containing a casing and a flowtubing in such a manner that the gas passes around the lower end of theflow tubing in a stream and in its passage gasifies the oil as it isstarted upwardly by the induced pressure in the well whether through thecasing or through the tubing depending upon the passage through whichthe gas is injected. Such methods operate effectively and efficientlywith a minimum pressure of gas aslong as the well is under flow but whenthe ow is shut down a vrelatively greater hydrostatic head of wellliquid accumulates and rises above Ythe point of gas discharge.Thisfhigh head of ungasified liquid cannot be overcome by a steadyapplication of gas under moderate flow pressure in a continuousdirection. This difficulty arises because when pressure of the gas isapplied to depress the liquid level in one flow passageway, thehydrostatic head is pushed higher in the other ow passageway and forcesthe liquid back into. the .producing formation until the oil volume inthe well be .decreased until its hydrostatic pressure head be reduced toa state below thatof the injected gas pressure so that this artificiallysuppliedgas can be forced downward and underneath the tubing into theoil column, at that point, into the oil column in the other ow pas-lsageway. Any attempt to directly start the well by straight applicationof gas pressure in order to force over the entire excess load ofaccumulated oil and uncoverv theA lower end of the tubing increases thehydrostatic head until it reaches the maximum, that is, until itis equalto the entire height of the flow passage which may bek several thousandfeet. It, therefore, is obvious that the required starting pressure mustbe at least equalV to the lished such equipment would not be neededandcould not be economically operated in maintaining normal flowpressure. To overcome this difficulty it has been proposed to start flowfrom deep wells by a rockover method by which a series of impulses iseffected in alternate directions through the respective passageways byalternately applying pressure to one passageway to depress the liquidlevel in that passageway and to raise the level in the other passageway.These impulses when properly timed cause the liquid to raise higher inone passageway and higher until the rising column is eventually forcedout of the top of the well, the action being assisted by the gas whichhas been absorbed under the pressure produced by the agitation resultingfrom the alternating or rocking movement. However, it is difficult tomanipulate the numerous Valves that are required to properly time theimpulses.

total ,hydrostatic head developed in the flow passageway, 'Y

It is also apparent that. after ow'has beenrestaba discharged from thewell.

Therefore it is the purpose of the present invention to provide a simplemethod and apparatus for starting flow by maintaining the rising andfalling columns under proper movement and timing to quickly andeffectively establish a continuous fiow in one direction.

In accomplishing this and other objects of the invention hereinafterpointed out, I have provided improved structure, the preferred forms ofwhich are illustrated in the accompanying drawings wherein:

Fig. l is an elevational view of a gas lift well equipped with a flowstarting apparatus constructed and arranged in accordance with thepresent invention.

Fig. 2 is an enlarged section through the single control valve showingposition of the valve for establishingilow of gas pressure in onepassageway and release of pressure through the other passageway.

Fig. 3 is a similar view showing the control valve in position toconserve pressure through transfer gas pressure above the respectivecolumns from one flow passageway to the other prior to application ofthe gas pressure supply.

Fig. 4 is a similar view showing the control valve in position forapplying pressure through the second passageway and releasing pressurefrom the first passageway.

Fig. 5 is an axial section through the valve on the line 5--5 of Fig. 4.

. Fig. 6 is yan elevational view of a modified form of startingapparatus employing discharge ducts separate from the flow startingducts. v

Fig. 7 is a sectional view through the control valve used in themodified form of apparatus.

Fig. 8 is a sectional view of a control valve similar to the controlvalve illustrated in Fig. 2 and which may be used in the modified formof apparatus.

Referring more in Adetail to the drawings:

1 designates a well extending from the surface of the ground indicatedat 2, to a liquid accumulating pocket 3 formed in a liquid producingformation 4. The Well 2 is provided with a casing 5 that is shown asextending from the producing formation to a point above the surface ofthe ground where it is provided with a casing head 6 having lateralconnections 7 connected with a flow pipe 8. Extending through a seal 9carried by the casing head vand depending into the well casing is a flowtubing 10 which connects through its lower end 11 with the interior ofthe casing 5 at a point in submergence by a column of well liquid thatis forced upwardly into the casing and tubing under normal formation orrock pressure. It is thus obvious that two flow passageways areprovided, one through the ow tubing 10 and the other through the annularspace 12 between the tubing and casing so that either one or the otherof the passageways may be utilized for the introduction of a Igaseouspressure medium and the other asaow passageway through which well liquidis In carrying out the present invention for beginning of a flow of thewell liquid through one of the passageways, the upper end of the tubing16 and pipe 3 are connected by branch pipes 13 and 14 with a controlvalve 15. Also connected with the control valve is a gas supply pipe 16by which gas is alternately admitted under pressure to pipes 13 and 14.Also connected with the valve is a liquid discharge pipe 17 forconducting the well liquid to a place of storage.

Located in the respective pipes adjacent the various connections withthe valve 1S are gauges 15, if: and 2i, which register pressure admittedthrough shutoff valves 22, 23, 24 and 2S respectively. The control valve1S includes a valve body 26 having circumfercntially disposed radialbranches 27, 2S, 29 and 30 that are adapted to be connected with thepipes 16, 14, 17 and 13 respectively. Extending transversely through thevalve body is a conical bore 31 in which is rotatably mounted a taperedvalve plug 32 that is adapted to be drawn into seal tight relation withthe bore by means of a nut that is applied to a reduced threaded end 34at the smaller end of the valve plug and which bears against the washer35 that seats upon a shoulder 36 encircling the smaller end of the boreas shown in Fig. 5. The opposite end of the valve plug has a reducedterminal 37 to which is attached a handle 38 by which the valves may beturned through three positions as later described.

As above stated, the normal formation pressure will cause the wellliquid to raise upwardly within the lower end of the tubing 10 andcasing 5 so that substantially high hydrostatic heads `are carriedwithin the well wherever the flow is shut down. When the well is flowinga gas under pressure is ordinarily admitted through the tubing 1t? anddischarged across the lower end 11 thereof 'for upward relief throughthe annular passageway 12 in such a manner that the gas intermixes withthe liquid in the casing and reduces the head thereof. so that theliquid ilows upwardly through the casing and is discharged by way of thecasing head or if desired, the gas pressure may be applied by way of thepassageway between the casing and tubing and the intermiXed fluids aredischarged by way of the tubing. When the liow has 'been shut down aswhen making repair to the equipment or as may be required inpro-rationing the production of a pro ducing area, relatively greathydrostatic heads of liquid accumulate in the well hole so that thelevel stands a material distance above the outlet end 13 of the tubing.Consequently, it is necessary to rst overcome this head before tlow canbe established from the well by means of a reasonable gas pressure. Aspreivously stated, this might be effected by introducing through thewell tubing or casing gas under sullicient high pressure to effectdepression of the liquid, for example, in the casing and lift a columnof liquid the entire height of the tubing, but, as previously stated, itis not practical to supply such high pressure and l have overcome this`difficulty by employing an improved rockover `method whereby gas underreasonable pressure is alternately admitted through the casing andtubing by means of the single control valve 26 through its variouspositions illustrated in Figs. 2 to 4 inclusive.

As shown in Figs. 2, 3 and 4, the plug member of the valve is providedwith laterally disposed arcuate ports 39 and 40 having the terminalsspaced apart around the periphery of the plug and 'from each othercorresponding with the spacing of radial channels 41 that are providedin the valve body to connect with the pipes 13, 14, 16 and 17. The valvecore is also provided intermediate the arcuate ports with a diametricalport 42 that is adapted to connect diametrically opposite pipes 13 and14 when the terminals of the arcuate ports are moved out of connectionwith the pipes 16 and 17 as shown in Fig. 3.

Assuming that the starting operation begins with seating of the valveplug in the position shown in Fig. 2 where the port 39 interconnects thepipes 14 and 16 and the arcuate port 40 connects the pipes 13 and 17,gas

Clt

under pressure 4is then discharged from the pipe 16 through the arcuateport 39 and pipe 14 into and through the passageway 12.

In this position of the valve plug, the tubing 10 is vented through theport 40 to the pipe 17. Pressure is then built up in the passageway 12from the supply pipe 16 to the available maximum pressure causing theliquid level to be depressed therein and the liquid level to rise in thetubing 19 to a point as high as possible or until the hydrostatic headof liquid in the tubing 10 equalizes the applied pressure in thepassageway 12. Under these conditions some liquid may be forced backinto the formation, thus further lowering the liquid level in thecasing. When a substantial equilibrium is obtained between the pressurein the passageway and the hydrostatic head in the tubing, the valve coreis turned to the position shown in Fig. 3. The gas pressure in thepassageway 12 is then transfered through the pipe 13, port 42 and pipe14 into the tubing. This conserves a portion of the gas under pressurein lthe passageway 12 and reduces the amount of gas to be injected intothe tubing 10 on the next cycle. This position of the valve issubstantially momentary, the time being determined upon inspection ofthe pressures indicated on the gauges 19 and 20. As soon as theindicated gas pressures are substantially equalized, the valve core ismoved to the position shown in Fig. 4 where the port 4i) connects thepipe 14 with the discharge pipe 17 and the port 39 connects the gassupply pipe 16 with the tubing 10. The gas in the passageway 12 is thenreleased through the discharge tube 17 and the full gas pressure isapplied through the tubing 10 to follow up gravity descent of the liquidlcolumn and thereby take advantage of the momentum and effectingelevation of the liquid in the passageway 12 to as high a level aspossible and depression of the level in the tubing to as low a point aspossible. These points having been reached, the valve core is returnedto the position shown in Fig. 3 where the high pressure in the tubing 10is transferred in part to the passageway 12. When the pressures aresubstantially equalized the valve core is turned to the position shownin Fig. 2 whereby the gas under pressure is again applied through thepassageway 12 and pressure is vented from the tubing 10 through thedischarge pipe 17, the momentum of the moving liquid again being reliedupon to assist the depressing of the liquid column as far as possibleand raise the column in the tubing. This alternate application of gasunder pressure on one side with released pressure on the other side, isrepeated as often as necessary and the liquid columns are thereby causedto surge back and forth in conjunction with the inuences of gravity andmomentum whereby an appreciable amount of agitation is produced andcontact of the liquid with the gas is increased with a resultantincrease in gas absorption, which absorption, of course, is materiallyassisted by the pressure under which the gas is introduced. The gravitydescent of one of the columns of liquid eventually reaches the end 11 ofthe tubing 10, for example, should the pressure in the tubing 10 depressthe column below the end 11, the gas will break through under the end ofthe tubing into the passageway 12 and if the column in the passageway 12is depressed to the end of the tubing, the gas will break through intothe column of liquid carried by the tubing 10. This breaking through ofthe gas under pressure effects atomization of the liquid in the highercolumn to eiect elevation thereof to the top of the well and dischargethrough the pipe 17.

All of the alternate pressure applications are easily and properly timedby the single control valve at intervals to correspond with thebeginning of the descent of the respective liquid columns, this timingbeing determined by watching the pressure gauges. The result is that thecolumns are caused not only to surge back and forth but also to risehigher and higher on the respective sides until a quantity of the liquidis sent over. It is important that this rocking or surging motion be sotimed as to obtain the maximum surge with the geratest possiblerapidity, since such timing results in taking the great advantage of themomentum of the moving liquid columns. In this fashion the combinedinuence of such momentum of the liquid bodies, together with thepressure under which the gas is introduced and the expansive influencesof the absorbed gas, eventually result in establishing continuous owfrom the Well.

In the present invention the single control Vvalve facilitates thistiming and assures that the application of gas pressure is applied atthe right moment whereby the ow is started with a minimum of cycles andin a shorter time period and with less gas.

In the form of the invention shown in Fig. 6, the passageway 43 betweenthe casing 44 and tubing 45 is connected through the casing head 46 withthe main ow discharge pipe Y47 having a shutoff valve 49 located thereinin spaced realtion with the casing head 46. The tubing 45 extendsthrough'lthe casing head 46 and is connected by a ow discharge pipe `50of similar capacity with the pipe 47 through a tting 51. The pipe 50 isprovided with a shutoifvalve 52 that is spaced above the casing head. Inthis form of the invention a gas pressure control valve 53 may beprovided which does not employ a diametrical passageway 42 intermediatethe arcuate ports 54 and 55 of the valve core 56. The valve 53 has fourbranches 57, 58, 59 and 60 similar to the valve previously described.The branch 58 constitutes the gas pressure inlet and is connected withthe gas pressure supply through a pipe 61. The branch 57 is connectedwith the tubing through a pipe 62 while the branch 59 is connected withthe pipe 47 by a pipe 63, the connections of the pipe 62 and 63 beingmade intermediate the casing head and the valves 49 and 52. The branch61 is connected by a vent pipe 64 with the discharge pipe 47 on thedischarge sides of the valves 49 and 52.

In this form ofthe invention, Vpressure is equalized between the tubing45 and passageway 43 surrounding the tubing through a bypass pipe 65that connects the pipe 63 with the tubingS. i The bypass is providedwith a shutoi valve 66. A pressure gauge 67 is connected in K the gaspressure supply line to indicate the supply pressure. Similar gauges 68are connected into the bypass 65 on the side of the valve 66 adjacentthe pipe 63 to register the pressure in the passageway 43. A pressuregauge 69 is also connected in the pipe 62 to indicate the pressure inthe tubing. A gauge 70 is also connected on the vent side of the valvesto indicate the discharge pressure.

In this form of the invention ow is started with the valves 49 and 52closed. The bypass valve 66 is also closed and assuming that the core ofthe control valve is set to connect the pipes 61 and 63, gas isdischarged under pressure into the passageway 43 to depress the liquidlevel therein and raise the liquid level in the tubing 45. As soon asthe gas pressure equalizes the hydrostatic head of liquid as indicatedby comparison of gauges 68 and 69, the control valve is closed byshifting the core to a position Where the ports 54 and 55 therein areout of register with the branch connections. The valve 66 is then openedto allow passage of gas under pressure from the passageway 43 into theupper end of the tubing 45. As soon as the gas pressure is equalized thevalve 66 is closed and the control valve 53 is moved to its otherposition where the supply of gas is discharged from the pipe 61 throughthe pipe 62 into the tubing 45 and the space 43 surrounding the tubingis vented through the pipes 63 and 64. The position of the valve core 56is thus alternated in conjunction with opening and closing of the valve66 to effect rocking of the columns of uid until a flow is establishedthrough the tubing 45 or pas- 6 sageway 4 3 as desired; vWhen theinitial flow is started to the discharge line through the pipe 62 or 63and onward through pipe 64, the valve 49 or 52 is opened to establishsubsequent flow -in bypassing relation with the control valve. Forexample, if flow is started through the tubing 45, the valve 52 will beopened so that the main flow is from the tubing through the dischargepipe 50. If ow is to be established through the passageway 43, then thevalve 49 will be opened and the ow is discharged directly to the pipe47. Otherwise the operation is the same as described in the rst form ofthe invention. If desired, the bypass 65 may be omitted and a controlvalve 71 provided with a diametrical port 72 as shown in Fig. 8 wherebythe operation will be the same as described in the rst form of theinvention with the exception ,that the main flow would not be carried onthrough the starting valve. y

From the foregoing it is obvious thatvI have provided a simplearrangement to facilitate timing of application of pressure iluid to therespective columns of liquid so that pressures may be applied at theright time and thereby reduce thetime and pressure medium required instarting the ow of a well.

What I claim and desire to secure by Letters Patent is:

l. An yapparatus for starting flow of a well under gas pressureincluding ducts extending into the well from the top andhaving terminalssubmerged in liquid* contained in the well, oneof which is adapted toserve as a conductor of well uid from the well and the other a conductor for the gas pressure into the well, a gas pressure supply duct, awell liquid discharge duct, control means having connections with all ofsaid ducts at the top of the well for alternately establishing flow ofpressure uid into one and then lthe otherof the well ducts and torelease pressure through the discharge ducts for lgasifying co1- umns ofthe well liquid in said ducts until one of said columns is elevated tothe discharge duct, and valved means connecting said well flow ducts forutilizing pressure in one well duct to initially repressure the otherduct when said other duct is connected with the discharge duct.

2. An apparatus for starting ow of a well under gas pressure includingducts extending into the well from the top lof the well and terminatingin submergence by liquid in the well, one of said ducts being adapted toserve as a conductor of well liquid from the well and the other aconductor for the gas pressure into the well, a gas pressure supplyduct, a well liquid discharge duct, a single control valve havingconnections with said ducts at the top of the well and having a valvingelement provided with ports arranged relatively to said connections andhaving positions to alternately establish flow of pressure liquid intoone and then the other of the well ducts and to release pressure throughthe discharge duct when the valving element is shifted through saidpositions, said valving element having a port 'adapted to interconnectsaid well ducts intermediate said positions of the valving element toutilize pressure in one well duct for initially pressuring the otherwell duct, and gauges connected with the respective ducts near saidconnections with the control valve.

3. The method of starting flow of well liquid in a well in which flow ismaintained by introducing a pressure fluid medium from a source ofsupply through one duct to effect upward llow of well uid throughanother duct with the ducts extending from above ground into the welland terminating below the liquid in the well, said method of startingthe ilow comprising passing a fluid pressure medium through one duct todepress well liquid in the said one duct and elect upward How of wellliquid in the said other duct until the pressure in said one duct andthe hydro-static head of liquid in said other duct substantiallybalance, shutting oit the source of pressure uid medium, transferringpressure fluid medium from said one duct into said other duct forconserving the pressure fluid medium and whereby the well uid drops insaid other duct and raises in said one duct, supplying the uid pressuremedium from the source of supply through the said other duct andsimultaneously releasing the pressure from said one duct to enhance themomentum of the rise and fall of well liquid in said ducts and increasethe rise of Well liquid in the said one duct, shutting off the source ofpressure uid medium, transferring the pressure iluid medium from thesaid other duct into the said one duct, and continuing said steps insuccessive order to effect an increasing rocking movement of the wellliquid downwardly in one duct and upwardly in the other in increasingmomentum until the Well liquid ows from the Wel 4. An apparatus forstarting flow of a well under uid pressure including ducts extendinginto the well from the top of said well and terminating in submergencewith liquid in the well, one of said ducts being adapted to serve as aconductor of well liquid from the well and the other a conductor for thepressure uid into the well, a pressure liuid supply duct, a Well liquiddischarge duct, a control valve, means for interconnecting all of saidducts at the top of the well with said control valve, said control valvehaving a valving element provided with ports arranged relatively to saidconnections and having positions to alternately establish ow of pressureuid into one and then the other of the well ducts and to releasepressure through the discharge duct when the valving element is shiftedthrough said positions, said valving element also having a port adaptedto interconnect with said well ducts intermediate said positions of thevalving element to utilize pressure uid in one well duct for initiallypressuring the other well duct.

5. An apparatus for starting ow of uid from a well under gas pressureincluding ducts extending from the top of the Well and terminatingwithin the uid of said well, a discharge duct connected with each of thewell ducts at the top of the well, a shutoi valve in each of saiddischarge ducts, a gas pressure supply duct, branch ducts connected withsaid discharge ducts on inlet sides of the shutoff valves, a singlecontrol valve interconnecting the branch ducts with the gas pressuresupply duct and having a valving element provided with ports arrangedrelatively to said connections of the supply and branch ducts and havingpositionsto alternately establish ow of gas pressure into one and thenthe other of the well ducts and to release gas pressure from thedischarge ducts when the valving element is shiftedthrough saidpositions forv eiecting alternate pulsations on the Well iluid untilflow is established to the top of the well through one of the well ductsto the discharge duct which is connected therewith, said shutoff Valvein that discharge duct being adapted to be opened to discharge said owof well fluid, and said valving element also having a port forestablishing connection between the well ducts intermediate saidpositions of the valving element for equalizing pressure in'said ducts.

6. An apparatus for starting flow of uid from a well under gas .pressureincluding ducts extending downwardly from the top of the well ,andlterminating within the well uid of s'aid well, main discharge ductsconnected with the Well ducts at the top of the well, shutoi valves ineach of the discharge ducts, -a gas pressure supply duct, branch ductsconnected with the well ducts on inlet sides of the shutoi valves, asingle control valve interconnecting the branch ducts and the gaspressure supply duct and having a lvalving element provided with portsarranged relatively to said connections with the branch ducts and havingpositions to alternately establish flow of gas pressure into one andthen the other of the well ducts and to release pressure when thevalving element is shifted through said positions for eiecting alternatepulsations on the well liquid until flow is established to the top ofthe well through one of the well ducts, said shutoff valve in that Wellduct being adapted to be opened to pass said ow of Well liquid throughthe discharge duct, and a valved bypass interconnecting said well ductsat a point on the well side of the shutoi valves for equalizing pressurein said well ducts between operations of the control valve.

References Cited in the le of this patent UNITED STATES PATENTS1,740,105 Lake Dec. 17, 1929 1,827,925 Wolcott Oct. 20, 1931 2,134,200Pivoto Oct. 25, 1938 2,340,481 Lloyd Feb. l, 1944

